The long-term objective of this project is a better understanding of family-genetic factors in depressive disorders, which are a major mental health problem, through use of the techniques of epidemiology and genetics. We propose a 3-year renewal to complete and extend the original 5-year study (May, 1976--July, 1981). Following the original specific aims, we have already (1) collected a unique set of data on families of bipolar, severely depressed, less severely depressed, and normal probands by interviews of multiple family members using the SADS-L; and (2) developed genetic models and analytic techniques appropriate to these psychiatric disorders and begun applying them to the data to investigate the role of genetic factors in clinical subtypes of depressive disorders. In the proposed continuation we will (1) complete the data analyses and write-up of the original study; (2) extend the data collection to include the assessment of children (age 6-18) of probands (a pilot study to develop and test the methodology for the assessment of children has been completed); (3) amplify the biochemical and genetic data on the families we are studying, and continue to develop genetic modesl appropriate for psychiatric traits; and (4) complete the analyses of the extended data base.